Photovoltaic cell and manufacturing method for photovoltaic cell

Abstract

The present disclosure relates to a photovoltaic cell and a method for manufacturing a photovoltaic cell. The photovoltaic cell includes a substrate including an emitter and a passivation layer stacked in sequence on one side of the substrate. The emitter includes a first plane and a second plane laminated along a thickness direction of the emitter, and part of the emitter between the second plane and the first plane is a first doped layer. Within a unit volume, a rate of change ΔC 1 between doping concentration of the second plane and doping concentration of the first plane satisfies: ΔC 1 ≤15%.

What is claimed is: 
     
         1 . A photovoltaic cell, comprising:
 a substrate ( 1 ) comprising an emitter disposed in the substrate, and   a passivation layer ( 11 ) stacked on a side of the emitter away from the substrate;   wherein the emitter comprises a first plane ( 12 ) and a second plane ( 13 ) laminated along a thickness direction of the emitter, and part of the emitter between the second plane ( 13 ) and the first plane ( 12 ) is a first doped layer ( 15 ); and   within a unit volume, a rate of change ΔC 1  between doping concentration of the second plane ( 13 ) and doping concentration of the first plane ( 12 ) satisfies: ΔC 1 ≤15%.   
     
     
         2 . The photovoltaic cell according to  claim 1 , wherein
 the substrate ( 1 ) is made of a silicon substrate material, and the silicon substrate material includes one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.   
     
     
         3 . The photovoltaic cell according to  claim 1 , wherein
 a third plane ( 14 ) is provided on a side of the second plane ( 13 ) away from the first plane ( 12 ), and part of the emitter between the third plane ( 14 ) and the second plane ( 13 ) is a second doped layer ( 16 ); and   a rate of change ΔC 2  between doping concentration of the third plane ( 14 ) and the doping concentration of the second plane ( 13 ) satisfies: ΔC 2 ≤30%.   
     
     
         4 . The photovoltaic cell according to  claim 3 , wherein
 the rate of change ΔC 1  between doping concentration of the second plane ( 13 ) and doping concentration of the first plane ( 12 ) and the rate of change ΔC 2  between doping concentration of the third plane ( 14 ) and the doping concentration of the second plane ( 13 ) within a unit volume satisfy: ΔC 1 <ΔC 2 .   
     
     
         5 . The photovoltaic cell according to  claim 3 , wherein
 a target element in the first doped layer ( 15 ) and the second doped layer ( 16 ) includes, but is not limited to, nitrogen, phosphorus, arsenic, boron, aluminum, gallium, indium, thallium.   
     
     
         6 . The photovoltaic cell according to  claim 3 , wherein a distance H 1  between the second plane ( 13 ) and the first plane ( 12 ) satisfies: 0.3 μm≤H 1 ≤0.35 μm; and
 a distance H 2  between the third plane ( 14 ) and the first plane ( 12 ) satisfies: 0.5 μm≤H 2 ≤0.7 μm. 
 
     
     
         7 . The photovoltaic cell according to  claim 1 , wherein, within a unit volume, a rate of change ΔC 3  between doping concentration at a first position of the second plane ( 13 ). 
     
     
         8 . The photovoltaic cell according to  claim 1 , wherein, doping concentration at a second position of the second plane ( 13 ) satisfies: ΔC 3 ≤25%. 
     
     
         9 . A method for manufacturing the photovoltaic cell according to  claim 1 , comprising:
 doping a target element into the substrate ( 1 ) to form the emitter; and   manufacturing the passivation layer on the first plane ( 12 ) of the emitter.   
     
     
         10 . The method according to  claim 9 , wherein a manner of doping the target element includes, but not limited to, high-temperature doping, post-oxidation doping, laser doping, and the like. Laser doping is adopted in the present disclosure, so as to control a doping depth. 
     
     
         11 . The method according to  claim 9 , wherein a third plane ( 14 ) is provided on a side of the second plane ( 13 ) away from the first plane ( 12 ), and said doping a target element into the substrate ( 1 ) comprises:
 coating the first plane ( 12 ) with a doping reagent ( 2 ) containing the target element;   directing a first laser ( 3 ) through the doping reagent ( 2 ) into the second plane ( 13 ) to diffuse the target element to the first doped layer ( 15 ) and the second doped layer ( 16 ); and   directing a second laser ( 4 ) through the doping reagent ( 2 ) into the third plane ( 14 ) to diffuse the target element of the second doped layer ( 16 ) to the first doped layer ( 15 ).   
     
     
         12 . The method according to  claim 11 , wherein said directing a first laser ( 3 ) through the doping reagent ( 2 ) into the second plane ( 13 ) to diffuse the target element to the first doped layer ( 15 ) and the second doped layer ( 16 ) comprises:
 directing the first laser ( 3 ) through the doping reagent ( 2 ) and the first plane ( 12 ) into the second plane ( 13 ), and generating a high temperature; and   driving the target element into the first doped layer ( 15 ) by the first laser ( 3 ) and further driving the target element to be diffused to the second doped layer ( 16 ) by the high temperature generated by the first laser ( 3 ).   
     
     
         13 . The method according to  claim 11 , wherein the first laser ( 3 ) and the second laser ( 4 ) are emitted by different laser emitters, and one of the laser emitters emits more than three laser of different wavelengths. 
     
     
         14 . The method according to  claim 11 , wherein said directing a second laser ( 4 ) through the doping reagent ( 2 ) into the third plane ( 14 ) to diffuse the target element of the second doped layer ( 16 ) to the first doped layer ( 15 ) comprises:
 directing the second laser ( 4 ) through the doping reagent ( 2 ), the first plane ( 12 ), and the second plane ( 13 ) into the third plane ( 14 ), and generating a high temperature; and   driving the target element to be diffused to the first doped layer ( 15 ) by the high temperature generated by the second laser ( 4 ).   
     
     
         15 . The method according to  claim 11 , wherein a wavelength L 1  of the first laser ( 3 ) satisfies: 300 nm≤L 1 ≤400 nm. 
     
     
         16 . The method according to  claim 15 , wherein a wavelength L 1  of the first laser ( 3 ) satisfies: 350 nm≤L 1 ≤390 nm. 
     
     
         17 . The method according to  claim 11 , wherein a wavelength L 2  of the second laser ( 4 ) satisfies: 400 nm≤L 2 ≤550 nm, and L 1 <L 2 . 
     
     
         18 . The method according to  claim 11 , wherein energy density W 1  of the first laser ( 3 ) satisfies: 0.4 J/cm 2 ≤W 1 ≤1.5 J/cm 2 . 
     
     
         19 . The method according to  claim 11 , wherein energy density W 2  of the second laser ( 4 ) satisfies: 0.6 J/cm 2 ≤W 2 ≤1.8 J/cm 2 . 
     
     
         20 . The method according to  claim 11 , wherein, after said doping the target element, the method further comprises:
 removing the doping reagent ( 2 ) remaining on the first plane ( 12 ).